Building for a computer centre with devices for efficient cooling

ABSTRACT

The invention relates to a structure of a multi-storey computer centre building which is suitable for accommodating a multiplicity of racks ( 202 ), each of which comprises storage space for computer hardware ( 101 ), wherein the building has a first cooling circuit ( 205 ) in order to dissipate heat generated by the computer hardware ( 101 ), wherein the first cooling circuit ( 205 ) is designed to supply at least some of the racks ( 202 ) with a coolant and the first cooling circuit is also designed to remove the heated coolant from at least some of the racks ( 201 ), wherein said racks ( 202 ) have heat exchanger devices ( 206, 207 ) which are suitable for transferring the generated heat to the coolant.

The present invention relates to a data centre building structure, whichis adapted to house a multiplicity of racks being designed to providestorage space for computer hardware. The data centre building isequipped with cooling means in order to provide dissipation of heatbeing generated by the computer hardware.

BACKGROUND AND PRIOR ART

In the prior art, there exist various data building structures forhousing a multiplicity of racks, each of which comprising storage spacefor computer hardware. For instance, a conventional data centre buildingaccording to the prior art is sketched in FIG. 1. It comprises a falsefloor for a computer infrastructure, which is typically housed in 19″rack enclosures. The cooling is accomplished by cold air, which ispumped into the false floors having holes at the appropriate locationsin front of the racks. In this way cold air is supplied at the airintakes of the computer racks.

Referring to FIG. 1, the floor 106 carries the false floor, assembledfrom vertical steel bars 107, carrying the floor tiles 104, 105, whichin turn carry the computer infrastructure, for instance 19″ racks 102.These racks 102 typically host 19″ rack mounted computer infrastructure101, which is horizontally mounted and acquires air at the front-side ofthe rack and produces warm air at the back side. In order to cool thecomputers, the false floor tiles have appropriate air holes 104, suchthat cold air 110 can be ingested into the racks 102.

In the prior art also an encapsulated cold air isle 103 is provided inorder to avoid, that hot air 109 short circuits the flow of cold air. Bymeans of such an encapsulation, the provided cold air 110, 111 may onlyleave the isle 103 via the computers' air intake and correspondinglythere is no other way for the heated air to enter this space.

This design is somehow disadvantageous, because the single racks 102have to be designed as closed racks. Further, the air flow throughrespective racks 102 has to be surveyed and controlled in order to avoidpumping unnecessary amounts of cold air from the cold aisle. There existvarious concepts, providing a regulation of the air flow into the coldisle 102, such that the fans providing the air flow 108 operate at thelowest possible power. The hot air 109 generated at the back of the rack102 is fed back to not explicitly illustrated heat exchangers beinglocated somewhere else in the data centre building. The heated air iseither cooled down again or fresh air is used in order to provide astream of cold air 108.

This architecture has various disadvantages. First of all, thecomparably small heat capacity of air requires rather high temperaturedifferences between the cold air and the heated air. Further, a high airflow rate with corresponding large losses due to air pumping is alsorequired. Reasonable limits of the air flow rate and the air temperaturelimit the overall size of the data centre building. Further, an aircooling system typically requires 40% of cooling overheat. Moreover, thefalse floor architecture is quite expensive and wastes volume inside thebuilding.

Document WO 02/052107 A2 further discloses a data centre buildingcomprising a ground floor and spaced lower and upper mezzanine floorsbetween the ground floor and a roof. Each of the mezzanine floors has anopen decking for allowing the passage of ambient air, whereby a forcedcirculation of ambient air is suggested in order to maintain the datacentre at acceptable operating temperatures. Even though this describedbuilding avoids the use of false or raised flooring by making use ofindustrial or warehouse space with mezzanine floor constructions, theheat dissipation mechanism is still not optimal, because a vast amountof cooling air has to be forced through the entire building structure,which is difficult to control and which is rather inefficient.

Also here, the overall building size is limited, because for anefficient cooling, the entire inner volume of the building has to besufficiently supplied with ambient air flow. Further, this architecturedoes not support multiple floors with large heating sources likecomputing racks, because the air temperature would rise more and moretowards the upper floors. The referred prior art only supports one floorwith rather low power density, for instance implementing networkequipment and one floor with computer infrastructure.

SCOPE

This invention is to provide a data centre and/or a data centre buildingstructure comprising more efficient and universal cooling mechanisms forcomputer hardware racks, thus, avoiding the necessity of guiding thecooling air across all racks. Further, the invention aims at optimisingenergy requirements and costs plus at arranging the computer racks moredensely in order to minimize the required length of the network cablesand to improve the system's communication capabilities. Compared tousual solutions, this invention is to provide a structure of a datacentre building comprising larger, scalable storage capacities and anincreased storage volume.

DESCRIPTION

The scope of the invention is accomplished by a data centre according toclaim 1, a rack for the computer hardware according to subordinate claim18 and a method for cooling the structure of a data centre building.

Pursuant to a first aspect, the present invention describes thestructure of a data centre and/or data centre building comprising atleast a first and second floor and/or a first and/or second storey andwhich is suitable for housing a large number of racks each of whichproviding space for computer hardware.

The storeys and/or floors are designed as a high rack warehouse.Therefore, they and/or the entire data centre building do notnecessarily have a floor; design and structure may be floor-free. Theusage of this high rack warehouse is particularly space-saving since itis possible to do without floors and, in particular, without doublefloors. Based on this method, the costs for a data centre buildingdesigned according to the invention may be reduced since high rackwarehouses are cheaper than normal data centre building structures.

Additionally, the data centre building comprises a first cooling circuitto discharge the heat generated by the computer hardware. This firstcooling circuit is designed to provide some of the racks with a coolant,and the first cooling circuit is designed to remove the coolant heatedby the computer hardware of at least some racks.

The invention is particularly characterized in that the aforementionedracks, which are connected with the first cooling circuit, comprise heatexchangers capable of transferring the entire heat generated by thecomputer hardware to the coolant. According to the invention, the heatexchangers' dimensions ensure they are capable of removing the entireheat volume generated by the computer hardware. Therewith, it is ensuredthat no hot air is released to the data centre. The air fed to the racksand the air coming from the racks have the same or even a lowertemperature so that it is possible to entirely avoid external,cross-rack air flows. Therefore, it is prevented that the roomtemperature increases in vertical direction.

In particular, the heat exchangers may be oversized so that the heatexchangers themselves contribute to cooling the data centre.

Therefore, the present invention is based on a complete rack-specificcooling system within the high rack warehouse and a transport mechanismin order to avoid the problem of how to provide and control a flow ofcooling air through the entire building. Instead, the first coolingcircuit requires little installation room only. Some or even allcomputer hardware racks are individually connected to the first coolingcircuit, which provides an efficient instrument for removing anddischarging the heat from the computer hardware.

Coupling each rack to be cooled to the cooling circuit individually withthe cooling circuit in connection with the rack-specific heat exchangerssuitable to remove the entire heat generated by the computer hardwareprovides the additional advantage that it is possible to control andmonitor the cooling power and heat exchange individually and separatelyfor each individual rack within the structure of the data centre.Cooling the hot air exclusively within the rack makes it possible toinstall any rack package densities without requiring air flow.

Based on this individual and separate cooling infrastructure it ispossible to arrange the racks within a high rack warehouse/multi-storeystructure since the entire environmental temperature of the building canbe maintained in a well defined, and rather low temperature range.Beyond that, the cooling system proposed allows using a so-called openrack architecture ensuring the racks do not need to be hermeticallysealed anymore.

According to a first preferred embodiment of the invention, the firstcooling circuit comprises a piping system to remove the coolant. Usageof a liquid coolant such as water and other suitable cooling fluids,particularly with larger thermal capacities than air, is advantageousdue to numerous reasons. At first, the total heat quantity that may betransferred and transported is, compared to gaseous coolants, larger.Secondly, it is possible to control and monitor the flow and thetransmission of the coolant more easily, compared to a turbulent andlaminar flow of a gaseous coolant.

Beyond that, it is recommended that the coolant is conveyed within thecooling circuit, which may contain water or any other liquid having acomparably high thermal capacity, with a pressure lower than atmosphericpressure. Based on this, it is guaranteed that not every leakage in thepiping system causes immediately loss of coolant escaping from thepiping system. Instead, the environmental air would enter into thepiping system and, based on this, prevent that sensitive and expensivecomputer hardware would be damaged by this coolant.

The storeys and/or floors of the high rack warehouse do, according toanother preferred embodiment, not have a false floor. Based on this,installation space is saved and package density of the computer hardwaremay be increased.

Beyond that, it is recommended that the coolant is conveyed within thecooling circuit, which may contain water or any other liquid having acomparably high thermal capacity, with a pressure lower than atmosphericpressure. Based on this, it is guaranteed that not every leakage in thepiping system causes immediately loss of coolant escaping from thepiping system. Instead, the environmental air would enter into thepiping system and, based on this, prevent that sensitive and expensivecomputer hardware would be damaged by this coolant.

The storeys and/or floors of the high rack warehouse do, according toanother preferred embodiment, not have a false floor. Based on this,installation space is saved and package density of the computer hardwaremay be increased.

Further, it is possible to reduce the difference in temperature betweenthe coolant supply and the computer hardware rack which is to be cooledto a minimum using an efficient insulation means within the pipingsystem, whereby it is simultaneously possible to remove the heatedcoolant from the building or feed it to a heat or cooling reservoirwithout heating the building itself unintentionally.

The heat exchanging means being arranged inside or in direct vicinity ofa computer hardware rack are adapted to transfer the entire heatgenerated inside the rack to the coolant. Therefore, the heat exchangingmeans of each rack to be cooled provide a heat coupling between theprovided coolant and the inner volume of the rack.

By means of the liquid coolant supplying piping, the entire buildingstructure can be designed in a universal and flexible way. Hence, incontrast to prior art solutions, various floors of the building do nolonger have to be permeable for ambient air flow. Also, there is nolonger a need to provide encapsulated cold air isles and additionally,it is no longer required to control a difficult-to-handle global flow ofcooling air inside a data centre building.

According to a further preferred embodiment, the data centre buildingstructure comprises at least a first and a second storey, which issupported by a steel support structure. Additionally, three or even morestoreys arranged on top of each other are conceivable and are in thescope of the present invention. In particular, the steel supportstructure may be designed as a high rack warehouse, wherein the steelsupport structure directly serves as a support for the computer hardwareracks. Therefore, floors segments or floor tiles to be arranged betweenthe various computer racks and the steel support structure are no longerrequired.

According to a further preferred embodiment, the racks are directlyarranged on double-T beams of the steel support structure. Further, meshgrids or comparable support structures can be arranged in the clearanceof adjacently located racks. Here, the mesh grids may serve as a kind offloor segment. Due to their mesh-like design, they allow penetration ofa directed air flow. Additionally, depending on the mesh size, thosemesh grids can also be optimized with respect to weight.

According to a further preferred embodiment, at least some of the rackscomprising a heat exchanging unit are adapted to transfer heat betweenthe coolant, which is provided by the piping, and a gaseous heatexchanging medium. Here, it is intended, that the gaseous heatexchanging medium is in thermal contact with the computer hardwarecomponents disposed inside the rack. The heated gaseous heat exchangingmedium is further in thermal contact with the heat exchanging unit andserves to transfer the accumulated heat to the liquid coolant inside thepiping.

In this way, the flow of a gaseous cooling medium can be reduced to aconfined space, in particular inside the respective rack. Hence, theheat exchanging means in combination with the liquid coolant are adaptedto provide a very effective means to prevent any hot air flow outsidethe racks. Hot air cannot escape from the inside of the rack to theoutside.

Furthermore, the heat exchanging means may directly receive the hot airgenerated by the computer hardware inside the rack and may transformthis hot air back down to a desired room temperature by simply conveyingthe heat to the coolant conveying piping. In this way, any routing ofhot air inside the data centre building can be avoided.

Also, the distance over which hot or heated air travels can be reducedto a minimum. It is only required to transport the heated air inside therack, in particular from the computer hardware to the heat exchangingmeans. In this way, any difficult-to-control turbulent air flow can beprevented. Instead, the invention comes along with a smooth and laminarair flow, which is basically constricted inside the rack.

Even though, a heat exchange between a liquid coolant and a gaseous heatexchanging medium is an easy and straight forward approach on how toprovide efficient and effective cooling, it is also in the scope of thepresent invention, that the heat exchanging medium used inside the rackis also liquid instead of gaseous. Hence, each rack may comprise heatexchanging means having appropriate flanges in order to couple therack-internal cooling architecture to the first cooling circuit, whichis adapted to interconnect various racks among each other and to conveythe generated heat to an external reservoir.

Another advantage of the rack-based heat exchanging means is, that theracks themselves do not have to be kept closed and that the air flowinto and out of the racks does no longer have to be controlled. As afurther benefit, inside the data centre building, there are noadditional air conditioners required, as the cooling function may becompletely taken over by the heat exchanging units inside the racks.

In particular, since the heat exchanging means comprise a rather largesurface, a relatively low and laminar stream of air can be obtainedinside the particular rack, thus allowing to reduce the speed ofoptional fans and to minimize a corresponding fan power consumption ofthe cooling.

According to a further preferred embodiment, at least some of the rackscomprise at least one cooling fan. Preferably, any of those racks havingheat exchanging mean comprise at least one fan, which is either directlycoupled to the heat exchanging means or which is disposed in closevicinity to the heat exchanging means in order to provide a sufficientcold air circulation inside the particular rack.

According to another embodiment of the invention, those heat exchangingmeans comprising at least one fan and a heat exchanger, are pair-wiseand adjacently arranged. In this way, the invention provides aredundancy in case, that one of a pair of heat exchanging means maybecome subject to malfunction. In such a case, the heat exchanging meansof an adjacently located rack may take over the function of that heatexchanging means, which is subject to failure. Further, the fan speed ofthe intact heat exchanging means can be individually increased in orderto compensate for the system failure of the neighbouring heat exchangeror its fan.

Therefore, it is of advance, that at least some of the racks comprisecontrol means for individually regulating the heat exchanging means. Inthis way, the entire system a may adaptively, locally react on localsystem failures and may automatically initiate respective provisions inorder to compensate the failure.

According to another embodiment, the control means further comprise leakdetectors for the piping and/or the smoke detectors, whereby saiddetectors are coupled to an emergency system, which is adapted toselectively switch off the hardware and/or the relevant branch of thecooling unit.

The emergency system may be designed and arranged in any of said racksindividually and separated from an emergency system of neighbouring oradjacent racks. Smoke and leakage detectors may be installed separatelyand independently from each other in order to individually switch offburning or stewing computer hardware and to be able to maintain allother operations of the data centre. Alternatively, it may also beimaginable to use a combination of individual detectors and/or to use amulti-functional detector.

According to a further embodiment, the racks further comprise powerscheduling means, that are adapted to keep an overall rush-in electriccurrent below a predefined threshold. This embodiment is adapted toprevent, that the entire data centre draws an amount of energy whichcannot be provided by an external power supply. Therefore, the powerscheduling means are adapted to regulate, that each rack or a pair ofracks draws power from an electric current- or voltage supply accordingto a given time sheet.

For instance, a first rack may power-up after a given time-delaycompared to any other rack of the data centre. In this way, peak-powerconsumption of the entire data centre building can be kept below apredefined threshold, thus ensuring, that the external power supply doesnot brake down. The power scheduling means may either be implemented asa specific algorithm assigning a predefined individual, hence different,time-delay to any of the racks of the data centre building.

Alternatively, it is also conceivable, that a power switch-on of thevarious racks is controlled by means of a centralised architecture.However, also an interconnected emergency system is in the scope of thepresent invention, whereby a multiplicity of leak-and/or smoke detectorsare electrically coupled to a central emergency system, which mayautomatically initiate respective provisions in order to counteract asystem failure.

According to another preferred embodiment, the data centre furthercomprises a second cooling circuit comprising the same principalstructure than the first cooling circuit. However, first and secondcooling circuits are alternately arranged in each storey of the datacentre building. In particular, if the racks in each storey are disposedin a row-or column-wise arrangement, every second column or row ofracks, for instance even numbered rows of racks are typically coupled tothe first cooling circuit whereas odd numbered columns or rows arecoupled to the second cooling circuit. In this way, even in case thatthe first or second cooling circuit may become subject to a malfunction,the remaining intact cooling circuit may overtake the entire cooling ofall racks of the relevant storey.

The compact architecture of the preferred embodiment allows to operatethe data center at relatively high ambient temperatures, therefore alsorising the temperature of the coolant liquid. Higher temperatures ofcoolant liquid allow more efficient cooling. In case the coolanttemperature approaching 30° C., the heat accumulated from the computerhardware may be used in order to heat other parts of a building, inparticular in wintertime without a necessity to make use of heat pumps.

According to another aspect, the first and/or second cooling circuit aredirectly coupled to heating means of a separate building or buildingunit being located in close vicinity of the data centre buildingstructure. By making use of a heated coolant temperature of around 30°C., surrounding buildings or building units can be directly heated bymeans of the heated coolant without the necessity of making use ofadditional devices, such as e.g. heat pumps. In particular, the coolingcircuit can be directly coupled to radiators or comparable heating meansof a building or building unit.

Furthermore, the first and/or second cooling circuit is adapted to becoupled to an external heat reservoir. This heat reservoir can be usedas energy buffer, for instance storing the heat accumulated from thecomputer hardware in winter during the night in order to provide morebuilding heating power during the day. In summer the heat reservoir canbe used for storing heat energy during the day, allowing to cool down atnight with higher efficiency due to colder ambient temperature.

According to a further embodiment, the double-T beams of the supportstructure, e.g. steel support structure may further serve as a guidingand support structure for a lifting device, being adapted transport andto lift entire racks of a storey across the storey plane. In this way,configuration and reconfiguration of the entire data centre building canbe facilitated without the necessity to provide any floor structure fortransporting of the computer hardware racks.

In another and independent aspect, the invention refers to a computerhardware rack which may be installed within a high rack warehouse in theabove mentioned data centre building. The computer hardware rackcontains storage room for computer hardware and at least one heatexchanger unit that can be connected to a cooling circuit conveyingcooling liquid. Beyond that, the computer hardware rack comprisescontrol systems that are designed to control the heat exchangers of therack individually and/or autonomously.

The heat exchanger is dimensioned in a way so that the entire heatvolume generated by the computer hardware is removed so that the heat isnot transferred to the environment of the rack.

In still another aspect, the invention provides a method for cooling ofa data centre building structure that comprises a multiplicity ofcomputer hardware racks, each of which comprising storage space forcomputer hardware. The method provides an approach to dissipate heatbeing generated by the computer hardware by the steps of conveying acoolant to at least some of the racks by means of a first coolingcircuit and by transferring the heat to the coolant by means of heatexchanging means and by finally conveying the heated coolant away fromthe racks to a cooling system by making use of heat exchanging meansarranged at each rack to be cooled. In this way an individual andseparate rack-wise cooling of a data centre building can be provided.Also, the cooling can be adapted to the cooling requirements of eachrack individually.

Furthermore, the method of cooling the data centre building ischaracterised in that the heat exchanging means are separately and/orautonomously regulated. This separate and autonomous regulation ofrack-specific heat exchanging- or cooling means allows to implement amulti-storey building structure with an increased packing or storagedensity which provides a sufficient heat dissipation, which can evenexceed a volumetric heat dissipation rate of 2 kW per m³.

By means of making use of a cooling circuit being adapted to convey aliquid coolant, the variety of the building architecture can beenhanced, since the coolant can be conveyed to any location inside thebuilding structure, where heat is generated by means due to computerhardware.

EMBODIMENT

In the following, preferred embodiments of the invention will bedescribed in detail by making reference to the drawings in which:

FIG. 1 schematically illustrates a data centre building according to theprior art and

FIG. 2 schematically illustrates a two-storey data centre buildingstructure according to the present invention.

In FIG. 2, two-storeys of the data centre building structure aredisclosed. The supporting structure of the computer hardware 101 isdesigned as a high rack warehouse, which comprises regularly arrangedT-beams 203, preferably comprising steel. The horizontal distance ofadjacent steel T-beams is adapted to the size and geometry of the racks202 providing storage space for the computer hardware 101. The high rackwarehouse has several floors 220, 221 in which the computer hardware 101is located in racks 202.

For instance, the distance of pairs of steel T-beams corresponds to thehorizontal elongation of the racks 202. In this way, the racks 202 canbe directly mounted onto the steel T-beams. However, the distancebetween pairs of steel T-beams may differ. In the illustration of FIG.2, a clearance 204 between adjacently disposed racks 202 may differ to aclearance 224. However, although not critically required, the clearances204, 224 are typically covered with mesh grid elements, allowing for apenetration of cooling air in the vertical direction.

In the illustrated embodiment of FIG. 2, any of the racks 202 comprisesa separate heat exchanging unit 206, which is equipped with a heatexchanger and with at least one fan 207 in order to facilitate thecooling air flow inside the rack 202. The heat exchanging units 206 areall coupled to a piping 205 conveying a liquid coolant, e. g. water, toany of the racks 202. Additionally, heat exchanging units 206 andappropriate fans 207 of pair-wise adjacently disposed racks 202 withinone row are designed to provide a redundancy in case, that one of theheat exchanging units 206 or appropriate fans 207 becomes subject tomalfunction.

In such cases, the heat exchanging unit 206 and the fans 207 of aneighbouring and adjacently arranged rack 202 may take over the coolingfunction of the dropped out heat exchanging unit.

The coolant supplied by means of a piping 205 is beneficial in that thevarious racks 202 no longer have to be designed as closed racks.Moreover, heat dissipation outside the various racks 202 can beeffectively reduced to a minimum. Hence, it is no longer necessary tocontrol a global air stream inside the building structure. In this waygeneration of hot spots which might be due to some turbulent hot airflow outside the racks 202 can be effectively eliminated.

Additionally, the airflow throughout the data centre building structuredoes no longer have to be actively controlled, since the ambienttemperature around the racks 202 is kept on a relatively could levelcompared to the temperature inside the racks 202.

In order to implement failure tolerance on the cooling infrastructure,the racks 202 can be operated in an even/old fashion, where every secondrack is coupled to the same piping, namely either the first or secondcooling circuit. In this way, two redundant cooling circuits can bemaintained providing a residual cooling capacity. The air pumpingcapacity of the heat exchanger fans 207 is preferably over dimensioned,which allows to compensate the loss of one fan by running the otherintact fans of the same or neighbouring rack 202 at an appropriatehigher speed.

In case of a failure, for instance due to a leak in the piping 205, aparticular rack can be selectively decoupled from the piping system 205.Such a decoupled rack 202 may be cooled byusing the adjacently disposedneighbouring racks as a kind of substitute cooling means, which may beoperated at a higher fan speed. Even if an entire cooling system fails,the second set of racks 202, being coupled to the second coolingcircuit, will take over the cooling of the next neighbours equivalentlyby operating its fans at an appropriate higher or even at maximum speed.In this way, the intact heat exchanging means and their cooling fans mayingest the hot air from their respective neighbours. However, if forinstance the cooling capacity may not be sufficient any longer, also thetemperature of the coolant may be lowered, thus immediately providing ahigher cooling efficiency.

Since there is no requirement to guide any air throughout the datacentre building structure, the computer hardware racks 202 can bemounted and disposed in any arbitrary arrangement, in particular bymaking use of the third dimension. In the embodiment as illustrated inFIG. 2, the racks 202 are mounted side by side and they are typicallyarranged in rows, facing front to front and back to back for optimalusage of the available space.

Other embodiments are imaginable, whereby the racks are arranged withfront side to rear side so that the next row absorbs the air directlyfrom the heat exchangers of the previous row. However, this scenarioneeds a bit more space since the distances between the rows of the racks202 must not be smaller than the length of a rack drawer, e.g. a drawerof 19 inch.

The coolant supply for each individual rack 202 is in particularlybeneficial, since it allows a multi-storey steel structure for computerhardware racks. In contrast, with conventional air-flow based coolingsystems, an upper limit of cooling capacity is rapidly reached, as soonas the data centre building structure has more than 2 storeys. Moreover,the purely air-flow based cooling becomes more and more inefficient withan increasing building size, in particular building with increasingbuilding height.

As further sketched in FIG. 2, the clear height required above the rackscan be kept at a rather low limit, for instance, at about 50 cm, leadingto storey height of 2.5 m, when racks of 2 m height are implemented. Thesteel support structure 203 not only carries the racks 202, but also lowcost grid floor elements 201, which are adapted to support maintenancework in such a high rise rack storey architecture. As a result, theentire building structure may comprise a steel grid, which can be builtat very low costs from standard building blocks. Different row pitchesand storey heights can be accumulated and/or adopted if required, simplyby moving the standard size T-beams 203. The open floor structure 201may additionally support air 208 flow between the various storeys.

The steel bars implement standard mounting for the cooling water piping205 and appropriate cable trays for the cabling 209, 210. Below everyrack row a standard longitudinal cable tray 209 is mounted by directattachment to the T-Bars as sketched in FIG. 2. Transversal cable trays210 are inserted, implementing a cable tray grid with an adjustablepitch. They are also attached to the T-bars like the trays 201. Theconnection to the longitudinal cable trays 209 is provided byappropriate holes in the castellated T-beams.

Vertical cabling is easily afforded between the racks top and/or bottomor by implementing vertical cable trays in spare locations. Thisarchitecture makes the ceiling of story n to the false floor of storyn+1. The implementation of the computer hardware in multiple storeysresults in the shortest average cabling distance for any given system,as this parameter rises only with the third root of the systems' volume.The rather open architecture allows the implementation of the shortestpossible cable paths between any two locations and therefore theshortest latencies between the nodes.

The bottom part of the T-bars carrying the racks can be used to supporta moveable hook with an attached hoist 212, 213, implementing a low-costmoveable crane, supporting the installation of heavy equipment.

The air flow in the racks can be optimised, implementing a lowtemperature difference between the hot spots inside the computer and theambient temperature. Assuming a state of the art temperature differenceof less than 20° C. between the ambient air and the hot spots inside therack 202, an air temperature of 40° C. is conceivable, allowing the heatexchangers to operate at 30° C. with a 10° C. temperature difference forcooling the air.

Rising the ambient temperature in the data centre therefore rises thecooling water temperature, which directly increases the coolingefficiency of the heated cooling water. The low cost floor space in thedata centre allows the usage of larger enclosures, such as 3U 19″systems or blade systems, using large fans and moving larger amounts ofair at lower speed. The fans 207 may assist this air flow, supporting toreduce the fan speed inside the computers further.

The fan speed in the heat exchanger is optimised according to the needsof the specific equipment in the rack. On one hand the consumed power ismeasured by detecting the primary currents into the computer, definingthe dissipated heat. The measured ambient air temperature and the heatexchanger's temperature define the required air flow for cooling andtherefore the fan speed.

On the other hand the ambient temperature at the top and rear side ofthe rack is measured. In case of insufficient air flow through the heatexchanger, this temperature will increase due to hot air leaving therack. Therefore, the performance of the cooling system is verifiedindependently in every rack.

In operation mode, all air leaving the computers of a rack flows throughthe appropriate heat exchanger. Therefore, it is possible to detectoverheating inside the rack by detecting smoke in the airflow. In caseof such a failure, the primary power to the computers in the rack can becut after attempting an emergency shutdown of the machines in the rack.Normal computers do not present a significant fire load and thereforethe disconnecting of the primary power will stop critical rise orescalation of the problem. Having control over the primary power in arack allows to schedule the power-on event, in order to limit therush-in currents. In the preferred embodiment of the invention theindividual racks negotiate a schedule for the powering-up of thecomputers.

An operating temperature of 30° C. allows the direct use of the coolingwater to heat nearby located office buildings, provided they implementfloor and wall heating. In summer, the data centre's heat can be used tocool buildings, using convection coolers.

The energy of the cooling water can be stored at night in a latent heatreservoir, where the office buildings require much less heating. Duringthe day the equivalent larger amount of heat is available for heating,matching the constant walk heat generation in the data centre with theduty cycle of the office building.

Another utility of the latent heat store is used in summer during peaktemperatures. During this time not all heat may be useable and may haveto be conveyed away. Since the cooling efficiency drops with increasingoutside temperature, the heat reservoir is used here during the day tostore the heat and to dissipate the amount of heat during night time,when the outside temperature is significantly lower.

REFERENCE LIST OF REFERENCE NUMERAL

-   101 computer hardware-   102 rack-   103 cold isle-   104 open floor tyle-   105 closed floor tyle-   106 ground floor-   107 false floor T-beam-   108 cold air flow-   110 air flow-   111 air flow-   112 false floor-   201 grid floor-   203 steel T-beam-   204 clearance-   205 piping system-   206 heat exchanging unit-   207 fan-   208 air flow-   209 longitudinal cable tray-   210 lateral cable tray-   212 crane-   213 crane-   220 storey n 222 storey n+1-   224 clearance

1.-19. (canceled)
 20. A multi-storey data centre building structurecomprising: at least a first and second storey, wherein the at leastfirst and second storeys are configured to house a multiplicity ofracks, each of the multiplicity of racks comprising storage space forcomputer hardware; a first cooling circuit for dissipating heatgenerated by the computer hardware, wherein the first cooling circuit isconfigured to supply at least some of the racks with a coolant, andwherein the first cooling circuit is further configured to convey acomputer hardware heated coolant away from at least one of themultiplicity of racks, wherein said at least one of the multiplicity ofracks comprise heat exchanging means configured to transfer a generatedheat to the coolant.
 21. The data centre according to claim 20, whereinthe coolant is transported within the first cooling circuit with apressure lower than atmospheric pressure.
 22. The data centre accordingto claim 21, wherein the first cooling circuit is designed as a vacuumsystem.
 23. The data centre according to claim 20, wherein the at leastfirst and second storeys do not have false floors.
 24. The data centreaccording to claim 20, wherein the at least first and second storeys aresupported by a supporting structure.
 25. The data centre according toclaim 20, wherein the multiplicity of racks are directly arranged atdouble T-beams of a supporting structure and wherein grid floors arearranged within the spacing between adjacent racks.
 26. The data centreaccording to claim 25, wherein the supporting structure is a steel beamstructure.
 27. The data centre according to claim 20, wherein the atleast one of the multiplicity of racks comprise heat exchangers designedto transfer heat between the coolant and a gaseous heat exchange medium.28. The data centre according to claim 27, wherein the heat exchangersand/or fans of adjacent racks installed in pairs are facing each otherwith their front sides.
 29. The data centre according to claim 20,wherein at least one of the multiplicity of racks are provided withcontrol systems to individually control the heat exchangers.
 30. Thedata centre according to claim 29, wherein the control systems comprisea leakage detector for a piping system, wherein said leakage detector iscoupled to an emergency system being configured to selectively switchoff the computer hardware and/or the first cooling circuit.
 31. The datacentre according to claim 29, wherein the control systems comprise asmoke detector, wherein said smoke detector is coupled to an emergencysystem being configured to selectively switch off the computer hardwareand/or the first cooling circuit.
 32. The data centre according to claim30, wherein the control systems are configured to switch off thecomputer hardware for each rack individually.
 33. The data centreaccording to claim 20, wherein the at least one of the multiplicity ofracks further comprise a system for switching on electricity suitable tomaintain an electrical starting current below a predefined limit. 34.The data centre according to claim 20, further comprising a secondcooling circuit, the second cooling circuit having the same structure asthe first cooling circuit, wherein the sections of piping systems of thefirst and second cooling circuits are alternately arranged in each rowof racks.
 35. The data centre according to claim 25, wherein the doubleT-beams are used as guiding and supporting structure for a liftingdevice
 36. The data centre according to claim 20, wherein the firstand/or a second cooling circuit is coupled to an external heatreservoir.
 37. The data centre according to claim 20, wherein the firstand/or a second cooling circuit is coupled directly with a heatingsystem of a separate building or building system, wherein the heatingsystem is configured to heat the building or building system.
 38. Thedata centre according to claim 37, wherein the heating system isconfigured to heat the building or building system preferably to 17° C.or higher.
 39. A rack for computer hardware to be arranged within thedata centre according to claim 20 within a high rack warehouse, whereinthe data centre is configured to have storage room for the computerhardware, the data centre further comprising a heat exchanger connectedto a cooling conveying liquid coolant, and wherein the rack furthercomprises a control mechanism to control the heat exchanger systemindividually and/or autonomously, and wherein the heat exchanger isconfigured to discharge the entire heat volume generated by the computerhardware so that a multiplicity of the racks does not emit hot air tothe data centre while in operation.
 40. A method for cooling a datacentre building structure comprising a multiplicity of racks in a highrack warehouse, each of which comprising storage space for heatgenerating computer hardware by the steps of: conveying a coolant to atleast some of the multiplicity of racks by a first cooling circuit; andtransferring the entire heat generated in the multiplicity of racks bythe computer hardware to the coolant by means for heat exchanging; andconveying a heated coolant away from the racks, wherein the means forheat exchanging are separately and/or autonomously regulated.